Variable-speed apparatus



Dec. 6, 1949 w. D. SHANNON VARIABLE SPEED APPARATUS 3 Sheets-Sheet 1 Filed June 26, 1947 Jaye/225m WQ/mmj. amp/20 6, 1949 w. D. SHANNON VARIABLE SPEED APPARATUS 3 Sheets-Sheet 2 Filed June 26, 1947 lam /2Z6 0 HZ/fd/Efl Ska/mom FAS OFF ON Dec. 6, 1949 w. 0. SHANNON 2,490,234

VARIABLE SPEED APPARATUS Filed June 26, 1947 s Sheets-Sheet s Patented Dec. 6, 1949 VARIABLE-SPEED APPARATUS William D. Shannon, River Forest, 111., assignor to General Electric X-Ray Corporation, Chicago, 111., a corporation of New York Application June 26, 1947, Serial No, 757,229 r 2': Claims. 1

The present invention relates in general to variable speed apparatus and has more particular reference to the generation of electrical energy, under variable speed conditions, the present invention being particularly well adapted for the production of pulsating electrical energy fluctuating at controlled variable frequencies for medical purposes.

In applying fluctuating electrical energy to patients for medical purposes it is desirable to be able to vary the frequency pulsations of the applied energy in a uniform glissando or gliding fashion, as distinguished from intermittent or stepped frequency changes. vFrequency variation in smooth progressive fashion not only minimizes sensory stimulation of the patient and resultant patient discomfort, but also allows for the" rapid determination of an optimum frequency adjustment for the treatment of the patient, it being understood that each patient responds best to frequencies within a definite range, which may be different for different patients, different for the same patient at different times, or for different body parts under treatment, or for different intensities of energy applied to the patient.

Accordingly, an important object of the invention is to provide variable speed apparatus readily adjustable or controllable in smooth, progressive fashion for operation at any desired speed within a wide range; a further object being to apply such smoothly adjustable, variable speed apparatus for the generation of alternating or fluctuating electrical energy at any desired and adjustably selected ,frequency within the frequency range of the generator.

* Another important object of the invention is to provide means for generating alternating current, preferably of sinusoidal wave form, at any desired frequency within a wide frequency range, including means for changing the frequency in progressive gliding fashion, throughout the frequency range of the generator.

Another important object is to provide means for producing electrical energy as'a fundamental or carrier wave of alternating character and of preferably sinusoidal wave form at any desired or selected frequency, including means for continuously modulating such frequency wave at any selected modulating frequency within the range of the device; a still further object being to provide for the variation of frequency of the fundamental or carrier frequency wave as well as the frequency of modulation of such wave in smooth, progressive fashion.

Another important object is to utilize an eddy current motor mechanism actuated by potential and current coils, in magnetic association with an eddy current disc, as a variable speed motor means for generating an electrical energy impulse wave at any desired frequency within the range of the apparatus, whereby the frequency of the generated wave may be altered in smooth, gliding fashion by controlling the energy applied to one or other. of the operating coils and preferably the current coil of the variable speed motor.

Another important object is to use an eddy current type motor, including a current and potential coil in association with an eddy current disc, for driving the modulating means; a further object being to provide the disc with an opening in position to stop the motor in a predetermined position with suchopening in registration with the actuatin coil magnets.

Another important object is to provide drag magnet means in magnetic association with the eddy current disc of the motor in order to provide for ultra slow speed motor operation.

Another important object is to provide for generating a fluctuating energy wave by interrupting a beam of light from a suitable source, at selected frequency, by "means of a slotted interrupting plate or disc turned in the path of the light beam by variable speed motor means of the character mentionedrphoto-electric elements in association with a suitable translation system being utilized to produce the fluctuating energy wave in response to the interruption of the light beam; a further object being to utilize a pair of photosensitive devices in combination with the light source and theslotted disc for producin alternatehalf-cycles of an energy wave of preferably sinusoidal form, the translation system being adapted to combine such alternate half-cycles of the wave to produce the complete energy wave.

Another important object is to provide an eccentric modulating dlschaving' edge portions in 5 position to move in the path of the light beam,

whereby to modulate the same, at a frequency determined by the rate of turning movement of said eccentric disc, and thus correspondingly modulate the energy wave produced as a result of the interruption of the light beam by 'the turning movement of a slotted wave generating disc, the slotted and eccentric discs being separately driven each by a connected variable speed motor, whereby the frequency of the fundamental or carrier energy wave, as well as the frequency at which the same is modulated by the eccentric disc, may be altered in smooth, progressive fashion throughout the frequency ranges of the apparatus.

Another important object is to provid an impulse wave generator of the character mentioned, including amplifying and translation equipment for producing a preferably sinusoidal carrier current wave at any desired frequency and modulated at any desired modulating frequency to provide,

an energy wave well suited for medical purposes in that it may be quickly and efficiently regulated for application with minimum discomfort to the patient.

Another important object is to provide an electro-medical apparatus having improved means for applying A. C. and D. C. energy selectively in an energy delivery circuit, including protective means preventing initial delivery of energy at high intensity in said circuit and means for the selective switching of indicating meters in conjunction with the application of energy in said circuit.

The foregoing and numerous other important objects, advantages, and inherent functions of the invention will become-apparent as the same is more fully understood from the following description, which, taken in connection with the accompanying drawings, discloses a preferred embodiment of the invention.

Referring to the drawings:

Fig. 1 is a perspective view of bodying the present invention;

Fig. 2 is'a sectional view taken substantially along the line 2-2 in Fig. 1;

Fig. 3 is .a front elevational view of the apparatus;

Fig. 4 is face view of'a control panel for the apparatus; and

Fig. 5 is a diagram of electrical connections.

To illustrate the invention the drawings show a main frame or chassis II providing mountings I2 and I2 for a pair of photo-electric elements I3 and I3 which are preferably mounted in side by side spaced apart relationship. The photo-sensitive elements I3 and I3 are preferably of identical construction, and may comprise photo-electric tubes or other photo-sensitive devices having electrical characteristics adapted to change in response to the application of light thereto and in proportion to the intensity of light impringing thereon. Photo-sensitive elements of the character contemplated are adapted for in terconnection in suitable electrical translation systems in which electrical energy waves may be developed, amplified and made available for use in accordance with the intensity of impinging light on the photo-sensitive devices.

The frame II also provides a mounting I 4 for a suitable lamp IScOmprising a light source in position to direct a beam of light I5 for the equal illumination of the photo-cells I3 and I3, the light source being spaced equally from both of the elements I3 and I 3'.

Asshown, the photo-cells and the lamp are mounted horizontally, with the lamp I 5 disposed above the medial portions of the sensitive elements of the photo-cells. While the horizontal arrangement of the lamp and photo-cells is not an essential feature of the invention, it is, nevertheless, a preferred arrangement for convenience of assembly and arrangement of the various coapparatus embperating elements of the apparatus.

If desired, the lamp I5 may be enclosed in anopaque housing having a lateral window facing toward the photo-cells and through which the beam of light may pass from the source equally to each of the photo-sensitive elements I3 and I3.

The frame It also provides a mounting for a beam modulating disc I6 drivingly connected with a variable speed motor H. The disc is carried on a preferably vertical axle pin I8 journaled in suitable bearings I9 and IS on the frame II, the disc I6 preferably extending in a plane at right angles with respect to the axis of the pin' I 8, and having an edge portion extending in position between the light source I5 andthe photo-sensitive elements I3 and I3. The disc I6 comprises opaque material and is provided with a plurality of radially arranged windows, which may conveniently comprise slots or openings 20 in the disc I6. These windows are preferably of wedgelike configuration, and are equally spaced apart in the disc I6. The windows are located in the disc portions which extend in the path of the beam I 5' so that, as the disc is rotated in the beam I5, the "slots 20 constitute light transmitting windows whereby the light beam is subdivided into light pulses for impingement on the elements I3 and I3.

As the disc I6 is turned in the light beam, each window, as it passes the light source, will allow a ray or beam of light to travel successively across and impinge upon the elements I3 and I3. As suming clockwise rotation of the disc I6, viewed in a downward direction, it will be seen that each window will thus first illuminate the element I3 and then illuminate the element I3; and the windows 20 are so spaced in the disc that each successive window will commence illumination of the element I3 as the preceding window, as aresult of its movement, discontinues illumination of the element l3. The windows 20 also are arranged to control the intensity of illumination of the elements so that each is illuminated in accordance with a sine wave, or other desired wave form. Accordingly, the elements I3 and I3 will be light actuated alternately to produce the alternate halfcycles of an alternating wave, having a desired wave form, and at an alternating frequency corresponding with the speed of rotation of the disc The speed of rotation of the disc I6 may be controlled by varying the power supplied to the motor I! which comprises an eddy current disc 2| on the stem I8 and driving magnets 22' and 23 disposed on opposite sides of the disc 2| and preferably comprising a magnet energized by a potential coil 22 and a cooperating magnet energized by a current coil 23. said magnets and actuating coils being suitably mounted on the main frame II.- By varying the energy applied to either of the coils 22 and 23, the rate of turning movement of the disc I6 may be correspondingly altered. Since it is easier to vary the current supply than to vary the voltage, it is preferable that speed control of the motor be obtained by varying the energizing current supplied to the coil 23, energy being supplied to the coil 22 at a constant voltage level. I

The speed of the disc I6, accordingly, may be varied uniformly within a normal speed range by controlling the current supplied to the coil 23, in smooth, progressive fashion whereby the frequency of light impingement on the elements I3 and I3 may likewise be altered in smoothly progressive fashion. Apparatus embodying the presentinvention may thus be controlled within a frequency range from two to one hundred cycles per second Means is also provided for-operation of the driving motor II at relatively slow speedtoproducelightimpingementontheelements it and it at frequencies inthe slow speed range between two cycles per minute and one hundred twenty cycles permlnute, that is to say, two cycles persecond, speed variation in the slow speed range being accomplished by control of energizing current to the coil it exactly as during high speed operation.

To accomplish slow speed operation, a drag magnet 24 may be provided. said. magnet comprising a core having pole pieces H and It suitably supported on the main frame ii in position, in facing registration on opposite sides of the eddy current disc II, and preferably located diametrically opposite the poles of the driving magnet, said drag magnet including an energisins collie inductively associated with said core to apply a magnetic drag on the disc II when said coil 26 is energized as by means of unidirectional current therethrough. Thus, by energinng the coils 2a, the motor ll may be caused to operate in its slow speed range at a rate of speed determined by the current supplied to the actuating coil 23; the motor operating in its high speed range as and when the coil 18 is unenergiaed.

The amount of light transmitted from the source I! through the windows 20 to the sensitive elements I: and it may also be modulated by a shutter 21 preferably comprising a circular disc eccentrically mounted on an axle pin II. The pin 28 may be Journaled in suitable bearings II and 29' on the frame II. The disc 21 preferably extends in a plane at right angles with respect to the axis of the pin 28, and has edge portions in position to extend between the light source II and the photo-sensitive elements it and II. The eccentricity of the disc 21 on the pin It is preferably such that the edge of the disc 21 on one side may entirely block light from the source II from passing through the windows 2., while the other side of the disc, when extending toward the light source/will allow light to pass from the source through the windows It freely and without any blocking whatsoever. Accordingly, as the disc 21 is turned, it may modulate the intensity of light beams l5 passing through the windows I. to the elements it and It, in accordance with a modulating wave form determined by the peripheral shape of the disc TI, said modulating wave form being preferably sinusoidal and its frequency being a function of the speed of rotation of the modulating disc 21. I

The modulating disc 21 may be driven by a motor 30 similar to the motor l1 and comprising an eddy current disc 8| on the stem 28, and driving magnets 32' and 33' disposed on opposite sides of the disc 3| and preferably comprising a magnet energized by a potential coil 31 and a cooperating magnet energized by a current coil I3, said magnets and actuating coils being preferably mounted on the main frame H. By varying the energy applied to either of the coils I! and 33, the rate of turning movement of the disc 21 may be correspondingly altered. Since it is easier to vary the current supply than to vary the voltage. it is preferable that speed control of the motor be altered by varying the energizing current supplied to the coil 33, energy being supplied to the coil 32 at a constant voltage level. The speed of the disc 21, accordingly, may be varied uniformly by controlling the current supplied to the coil I! in smooth, progressive fashion whereby the frequency of modulation of the light beams I! may 8 likewissbealteredinsmoothlyprogressivefasb' ion.

It is desirable thus to control modulating frequmcywithinaslowspeedrangebetweentwo cyclesandsixtycycluperminute. Thisslow speed operationmay beaccomplishedby-means of a drag magnet 84 suitably mounted on the frame ll inposition to face one side of the disc II in position diametrically opposite from the poles of the driving motor. This drag magnet 34 ofcoursemaycompriseacoilenergizedata constantenergy level. although it is convenient to employ a permanent magnet, as shown, for the reason that the motor-l0 is not required to operate at speeds other than in the slow speed range.

As shown more particularly in Fig. 5 of the drawings, the photo-cells It and. It may be interconnected in an electronic'translation system II which operates to produce alternating current of wave form and frequency corresponding with the variation in light intensity on the elements It and II accomplished by the light interrupting disc II and the modulating disc 21, said translation system II serving to make such alternating' current available for application to a patient at the patient terminals 40.

To this end the system shown in Fig. 5 may be energized from .a suitable source of alternating current power 31, power being delivered from said source through control switches 34 between conduotor bussos 3! and 4|, a pilot lamp 4! being provided for indicating the active or inoperative condition of the equipment.

The power supply lines 39 and 40 may be connected to energize a D. C. power supply system 42. While any suitable or preferred D. C. power supply system maybe utilized, the drawings show a system 42 embodying transformer means 43, and preferably thermionic rectiflers 44, 44' and 4|, also resistance elements and condensers interconnected together and with the rectifiers, including adjustable resistors 46 and 41 to provide unidirectional power at desired potentials on supply conductors 48, 48, ill, BI and 52. In the illustrated system the conductors 48 and 4!, respectively, carry 13+ and B potential of fixed value. The conductor ill, which is adjustably connected with the resistance potentiometer 41, carries adjustable bias control potential for the operation of the translation system 35 in a manner hereinafter more fully described. The conductors El and 52, the former of which is adiustably connected with the resistance potentiometer 40, carry unidirectional energy at adiustabie potential for the operation of the drag magnet coil 26, which is interconnected between said conductors SI and 52 through a preferably manually operable on-and-off switch 53.

The bus conductors l9 and 40 also supply A. C. energy for the operation of the motors l1 and 30 through supply conductors 39' and 40', the conductor being directly connected with the power bus 39 and the conductor 40 being interconnected with the power bus 40 preferably through voltage regulator means 54 which serves to maintain at a constant level the A. C. voltage on the supply conductors 39' and 40'. The voltage regulator means 54 is preferably interconnected with the power busses 39 and 40 and with the supply conductor 40' by means of a detachable plug-in connector, and the conductor 40' is preferably interconnected with the power bus 40 by means of a circuit including a switch 55 adapted to remain open so long as the voltage regulating means 54 is operatively connected, the

, switch 33 closing is associated with the Mean and remaining closed as and when the voltage regulating means is nected from the conductors 33 and 43 and 43'. Accordingly, the apparatus may be operated without voltage regulation accomplished by the regulator means I4 by disconnecting the same and closing the switch It.

- Control means 53 for operating the motor means I! and 30 comprises electrical means powered from the conductors 33' and II, said electrical means being interconnected between an extension of the conductor 39' and an auxiliary conductor 40" adapted for connection with the conductor 40 as by means of a switch II. To this end the potential coils 22 and 32 of the motors II and 30 may be connected directly and permanently between the conductors 3| and ll".- The current coils 23 and 33 of the motors may be conducted each preferably with the secondary winding of a corresponding step-down transformer 23" and 33", the primary windings of said step-down transformers being connected on one side with the conductor 33' and on the other side through calibrating resistors it and 53' and manually adjustable speed varying resistance potentiometers I3 and It, said potentiometers 59 and 39' being interconnected between the conductors 33' and 40". By adjusting the calibrating resistors 58 and 53', the motors l7 and 30 may be calibrated for operation within a desired normal speed range under the control each of its associated potentiometers 59 and 59'. Manual adjustment of the resistors 59 and 59 as against separate index scales will adjust the motors for operation each at a selected speed within the adjusted range.

It will be apparent from the foregoing that energizing power will be supplied to the motors upon operation of the switch 51 to connect the conductor 40'' with the power supply conductor 40. While it is unnecessary to provide for the stoppage of the motor I! other than by means. of the switch 57, means is provided for stopping the modulating motor 30 while continuing the motor I! in operation. To this end the disc ii of the motor 30 is provided with an opening 68 therein in position to pass between the facing poles 32' and 33' of the current and potential coils of the motor 30. This opening will not interfere with the operation of the motor unless the energy supply to one or the other of the operating coils 32 and 33 is substantially reduced. Accordingly,

the motor will operate at uniform speed so long as both coils 32 and 33 are fully energized. By cutting down the energy supply to either coll the motor will continue to turn at ultra slow,

speed and in creeping fashion until the opening comes into registration with the center of the facing magnet poles 32' and 33', when the motor will stop. The opening I is preferably positioned in the disc 3i to register with the poles 32' and 33 when the shutter disc 21 is in a position of minimum or no modulation of the light beams l5.

In order to provide for thus controlling the motor 30, a manually operable preferably singlepole, double-throw switch 6! may be provided in the energizing circuit of the motor coil 33. As shown, the pole of this switch ll may be connected with the calibrating resistor 58' which primary winding of the transformer 33". One of the contacts of the switch 5l 'may be connected with the potentiometer 59', so that when the switch blade is engaged with said contact the motor may operate at normal speed underthe control of the adjustable potentiometer 58. The other contact oi. the switch Ii may be connected with the potentiometer 59', as at a fixed tap thereon, through a fixed resistor 32 so that when the switch blade is moved into engagement with said other contact, the energy supplied to the current coil 33 will be reduced as a result of the connection of the resister 62 in the energizing circuit. The motor 33 will thereafter operate at ultra slow creeping speed until the opening 60 of the disc 3| registers with the pole pieces 32 and 33 and stops the motor.

The exciter lamp or light source l5 may be energized by connection with the secondary winding of a step-down transformer 63, the primary winding of which is energized by connection between the conductors 39' and 40" in series with a preferably manually adjustable resistor 64.

The translation apparatus 35 comprises the light cells 53 and I3, impedance matching electron fiow valves 65 and 65', and electron flow valves 66 and 66' forming the input of a bridge circuit 8?. This bridge circuit comprises a resistance network and electron fiow valves 68 and 65. The anodes or plates of the photo-electric devices it and i3 and of the valves 65 and 65', 66 and 86' are all interconnected with the conductor d8 carrying B+ potential. The light cells l3 and it are interconnected in push-pull relationship, respectively controlling the grids of the impedance matching valves and 65', the oathodes of the photo-cells being preferably resistance coupled as through manually adjustable resistors 69 and 69 with the conductor 49 carrying 3- potential. By adjusting the resistors 69 and 69', the photo-tubes may be calibrated for matched or equalized operation to accommodate for any discrepancy or manufacturing inequality of the operating characteristics of the tubes.

The impedance matching elements 65 and S5 operate as cathode followers to match the impedance of the photo-cells with that of the input valves of the bridge circuit 67, the cathodes of the valves 65 and 65 being resistance coupled with the conductor it, carrying B"- potential and said cathodes of the valves 65 and 55' being respectively connected with the control grids of the bridge circuit input valves 66 and 66f.

The bridge circuit 67? comprises the electron flow valves 65, 6B, 63 and 68', and interconnecting matched resistance elements, in push-pull relationship, the cathodes of the valves 66 and 685 being interconnected respectively with the anodes of the valves 68 and 68', and with output conductors iii and l8.v The grids of the valves 68 and 68' are interconnected through matched resistance elements with the 1 conductor at through which a variable grid bias may be applied to said grids from the adjustable potentiometer 37. The grids of the tubes 68 and 68' are also interconnected respectively through matched resistors with the conductors l0 and it.

As the current in the output tube 66 increases and decreases under the control of its grid, in turn actuated by the cathode follower tube 65 under the influence of the photo-tube is during a half-cycle of light impingement thereon, the voltage applied to the grid of the tube 68 will correspondingly increase and decrease, thereby correspondingly varying the voltage between the lines it and Hi, which, as hereinafter explained, may be connected with the patient through the outlet plug 36. During the alternatehalf-cycle of operation, voltage will be varied in the oppoaccess site direction as a result of the decrease and increase in voltage across the tube 88', which, operating through the tube 88', will deliver a rising and falling potential between the conductors 18 and 18'. During one half-cycle of operation the current will flow in one direction through the patient, and it flows in the other direction during the successive or alternate halfcycle.

Suitable center-tapped transformers 12, 18 and 14 may be employed for energizing the filaments of the electron now valves 88, 88', It. ll, 88 and 88. The primary windings of the transformers 12, 18 and 14 may be connected between extensions of the conductors 88' and 48'', whereby said transformers may be energized under the control of the switch 51. The transformer 12 is preferably connected to energize the cathode filaments of the valves 8! and 88, the cathode element of the valve 88 being connected with the center tap of said transformer. The transformer 18 is preferably connected to energize the cathode fllaments of the valves 88' and 86', the cathode element of the valve 88 being connected with the center tap of said transformer. The transformer 14 is preferably connected to energize the cathode filaments of the valves 88 and 88', the cathode elements of the valves 88 and 68' being connected with the center tap of said transformer and with the conductor is carrying .8- potential.

The apparatus includes switching means, including the switch 51, and a pair of switches 15 and 18 for interconnecting the motor means i1 and and the power busses 88 and ll for operation, and for connecting the conductors Hi and 10' with the patient plug 88, said switching means serving also to selectively apply fluctuating energy from the translation system 85, and unidirectional energy from the D. C. power supply system 42 to the patient plug 88; and the switching means also serves to interconnect indicating meters 11 and 11' in the system.

To this end the switches 81, 15 and 18 preferably comprise single-pole, double-throw switches having each a normally open and a normally closed contact. The pole or blade of the switch 51 is connected with the supply conductor 48', and its normally closed contact is connected with the conductor 89 through the operating coil 18 of a relay switch 18. The normally open contact of the switch 51 is' electrically connected with the motor energizing conductor and also with the conductor 89 through a switch 18 and an operating coil 18' of the switch 18. The

' switch 19' is interlocked with the switch 53 so that both switches open and close together. Accordingly, the switch 18 will be closed to energize the coil 18' when the switch 58 is closed for the slow speed operation of the motor i1.

When the switch 51 is in its normal position, the conductor 40" will be inactive together with the motor operating mechanism 56, as well as the cathode energizing transformers 12, 13 and 14 of the translation system which will likewise be inoperative. The operating coil 18 of the switch 19, however, will be energized when the switch 51 is in its normal position.

The switch 19, like the switches 51, 15 and 18, is a single-pole, double-throw switch having a normally closed contact connected with one side A of the patient plug 88, said side of the patient plug being also connected through a selector switch 80 to the meter 11. This meter preferably range operating coils connected with the switch II which normally closed on the high range coil, being alternately eonnectible at will with the low range coil. The other side of the meter 11 is electrically connected with the blade of the switch 18 which is also connected through a single-pole, double-throw switch II with conductor means adapted for connection with the high, intermediate and low range coils of the meter 11, said meter preferably comprising an A. C. meter. The switch II has a normally open contact connected with'the low range coil of the meter 11', and a normally closed contact connected with the blade of a single-pole, double-throw selector switch 82 having a normally open contact connected with the intermediate range coil of the meter 11' and a normallyclosed contact connected with the high range coil of the A. C. meter. The common side of the A. C. meter is connected with the normally open contact of the switch 18, said normally open contact of the switch 18 being electrically connectible as by means of a reversing switch 88 with one or other of a pair of conductors 84 and 85, said reversing switch serving to connect the conductors 84 and I, one with the normally open contact of the switch 18 and the other with the side B of the patient plug, and to reverse said connections. Accordingly, the switch 18 operates to connect either the D. C. meter 11 or the A. C. meter 11' in series circuit with the conductors 84 and II to the patient plug, whereby said meters may indicate the value of current delivered through the plug to the patient. When the switch 18 is in its normal position, it will short circuit the D. C. meter 11, thereby connecting the A. C. meter in circuit. When the blade of the switch 19 is shifted to engage the normally open contact, the A. C. meter 11' will be short circuited and the D. C. meter connected in circuit. The meter switches 8i and 82 normally connect the A. C. meter for high voltage operation, the switch 82, when moved from its normal position, will connect the meter for operation in its intermediate voltage range, and the switch 8|, when shifted from its normal position, will connect the meter for operation in a low voltage range.

The conductor 84 connects with the blade or pole of the switch 18. The conductor 85 is connected with the pole or blade of the switch 15, through a control switch 88 and an adjustable potentiometer resistance 81, the opposite ends of which are respectively connected with the blades of the switches 15 and 16. Electrical energy applied between the blades of the switches 15 and 10 may thus be delivered through the conductors I! and 84, to the patient, by way of the plug 88, the reversing switch 83, and whichever meter is connected in circuit by operation of the switch 18, at a potential determined by the adjustment of the potentiometer 81, provided that the switch I! is closed. The switch 86 is normally open but may be closed by an operating solenoid 88' when energized. Said solenoid 88 is preferably connected in series between the conductors l8" and 40 through an actuating switch 88. The switch 88 preferably comprises a normally open micro-switch in position to be closed by the adjustable member of the potentiometer 81 when it is at the end of the resistance element of the potentiometer which is connected with the blade of the switch 16, that is to say, when the voltage between the conductors 84 and ll is zero. The solenoid 86' accordingly may be comprises a D.. C. meter having high and low 76 energized to close the switch 86 only when the 11 conductors 88 and 88 are short circuited, thus obviating the possibility of initially applying energy at high intensity to the patient. After the switch 88 has been closed by operation of the potentiometer to zero voltage position, the switch 86 will be closed by operation of the solenoid 86', whereupon circuit energy may be increased to any desired extent by operation of the potentiometer 81, the amount of applied current being indicated by whichever of the meters'11 and 11' is connected in circuit. To hold the switch 86 closed after operation of the potentiometer to increase the voltage on the patient leads 88 and 85, a holding switch 89 may be provided to maintain the energizing connection of the coil 81 with the conductor 39 after the switch 88 shall have opened. The switches 88 and 88 are nected to close and open together, so that upon closure of the switch 88 the switch 88 will also close and thereafter remain closed until the apparatus is disabled as by the opening of the master switches 38. When the switches 38 are opened, the solenoid 81 will become de-energized, the switches 86 and 89 will open, and may not thereafter be closed unless and until the potenitometer 81 is adjusted to zero voltage position following the closure of the master switches 88 to recondition the equipment for operation.

It will be seen that the switches 15 and 16 normally connect the patient leads with the output conductors and 10 of the translation system 35. Accordingly, the A. C. output of the translation system will normally be connected with the patient leads, and A. C. energy will be delivered upon closure of the switches 38 and the operation of the switch 51 to connect the conductor 80 with the conductor 80". Thereupon, the motors I 1 and 38 will be set in operation at'speeds determined by the potentiometers 58 and 58 and the drag magnet switch 53, the light source l5 will be energized, and the translation system 35 will be operated to deliver the A. C. output of the translation system through the switches and. 16 to the patient leads 84 and 85, energy being applied to the patient only after closure of the switch 88 as the result of manipulating the potentiometer 81 to its zero voltage position. At the same time, the switch 51 will energize the solenoid coil 18' in the event that the switch 19' is in the slow speed position, and the coil 18', when energized, will move the switch blade into engagement with the normally open switch contact to thereby interpose the D. C. meter 11 in the patient circuit. The D. C. meter is responsive to alternating currents at frequencies within the range produced when the motor I1 is operating at slow speed, that is to Say. a frequency range from two cycles to one hundred twenty cycles per minute. When the switches 53 and 19' are open, however, during normal speed operation of the motor H, the coil 18' will be de-energized so that the switch 19 will be in its normal position interconnecting the A. C. meter 11' in the patient circuit.

Obviously, the switches 88, 8| and 82 should be adjusted so that the meters may be conditioned for operation in their high, intermediate or low ranges, depending upon the amount of current delivered in the patient circuit.

The apparatus may also be controlled to deliver D. energy in the patient circuit by moving the blades of the switches 15 and 18 into engagement with the normally open contacts of said switches, said contacts respectively being coninterconbe mounted on a panel 98 in tioned for D. C. operation in nected with the conductors 88 and 89 carrying 3 and B" potentials, the switch 81 occupying its normal position to interconnect the switch solenod 18 between the conductors 89' and 40' through the switch 81, to thereby actuate the switch 19 to interconect the D. C. meter 11 in the circuit, to indicate the value of current flow in the patient circuit. Operation oi the switch will determine the high or low range 01' operation of the meter 11, and the switch 83 will determine the polarity of D. C. energy delivered to the patient through the plug 38.

For convenience or operation and control, the several switches and adjustable devices required for the operation and control or the system may which a manually operable handle 9| is provided for actuating the switches 88, 51, 15, 18, 88, 8| and 82. The control knob 8i may occupy any one of several positions, including a central "ofl" position in which all of the control switches 88, 51, 15, 18, 88, 8| and 82 occupy their normal positions, the apparatus being inoperative since the switches 88 are normally open.

On one side of the "01? position, the control member 9i may be set for D. C. operation in either a high or low voltage range. When posi the high range, the switches 88, 15 and 16 only will be thrown from their normal position to thus close the normally open switches 38 and move the switches 15 and 18 to connect the patient circuit '84, 85 with the D. C. power conductors 48 and 49, thereby setting the apparatus for delivery of D. C. energy to the patient through the plug 36. For D. C. operation in the low range, the switches 38, 15, 18 and also 88 will be moved from normal position to thereby connect the D. C. meter 11 for operation in the low range.

The control member ill may also be shifted from the neutral position to any one of three controlling positions for A. C. operation in low, intermediate and high ranges. When positioned for operation in the high range, the switches 38 and 51 only will be moved from their normal position whereby the meter 11' will be interconnected in the delivery circuit for operation in the high range. Theintermediate range setting Of the member ti will move the switches 38, 51 and 82 from normal position to thereby connect the meter F1 in circuit for operation in the intermediate range; while the low range setting throws the switches 38, 51 and it i.

A manually operable control knob 92 also is preferably provided on the panel for operating the intensity control potentiometer 81; and similar manually operable control knobs 93 and 98 may also be provided respectively for controlling the speed varying Potentiometers 58 and 58 of the carrier current and modulating motors l1 and 36.

The panel as may also provide support for the patient plug 86 and a manually operable knob for controlling the reversing switch as; and manually operable members 85 and 86 may be :provided, respectively, for actuating the stop and go switch 8! 0f the modulator motor and for actuating the high and low speed range switches 53 and 19'.

lit will be seen from the foregoing that the present invention contemplates apparatus readily operable and easily controllable for the production and application to patients of A. C. energy in the form of a wave at frequencies continuously variable in stepless fashion within an unusually wide frequency range, as, for example, from two 13 cycles per minute to six thousand cycles per minute, while delivering energ up to a maximum of the order of one hundred milliamperes. This output may be modulated at will at a moduatin frequency within a desired frequency range such as from two cycles per minute to sixty cycles per minute; and the apparatus is also capable of delivery of D. C. energy at any desired value within the range of the equipment, as up to one hundred milliamperes, the delivery of D. C. or A. C. energy being incidentally selectable at will.

The apparatus includes the important safety feature that whenever the apparatus becomes inactive, as at the conclusion of a treatment period, it cannot be re-activated except in condition to deliver zero energy to the patient, through the outlet plug 36, whereby in initially applying energy, the patient can never be subjected to an energy jolt or high intensity energy shock.

Since the alternating energy output is generated by the interruption of a light beam by the slotted disc IS, in turn driven by a continuously variable speed motor, it may be altered in smooth, continuous, stepless fashion throughout the frequency range of the apparatus, and the modulating frequency likewise may be continuously varied to the end that patient discomfort is reduced to a minimum, and the application of alternating energy to the patient at an optimum frequency may be expeditiously accomplished.

It is thought that the invention and its numerous attendant advantages will be fully understood from the foregoing description, and it is obvious that numerous changes may be made in the form, construction and arrangement of the several parts without departing from the spirit or scope of the invention, or sacrificing any of its attendant advantages, the form herein disclosed being a preferred embodiment for the purpose of illustrating the invention.

The invention is hereby claimed as follows:

1. Apparatus for production of electrical energy comprising means operable to provide a D. C. power supply, generator means for producing A. C. energy. means forming an output circuit.

' switch means selectively operable to connect said power supply and said generator means alternately in said output circuit, A. C. and D. C. indicating meters, and switch means operable for interconnecting said meters in said output circuit as said power supply and generator means are connected therewith.

, 2. Apparatus for production of electrical energy comprising means operable to provide a D. C. power supply, generator means for producing A. C. energy, means forming an output circuit, switch means selectively operable to connect said power supply and said generator means alternately in said output circuit, A. C. and D. C. indicating meters, switch means operable for interconnecting said meters in said output circuit as said power supply and generator means are connected therewith, and a polarity reversing switch in said output circuit.

3. Apparatus for production of electrical energy comprising means operable to provide a D. C. power supply, generator means for producing A. C. energy, means forming an output circuit. switch means selectively operable to connect said power supply and said generator means alternately in said output circuit, intensity control means in said output circuit and switch means for holding the output circuit normally inactive, said switch means being operable by said intenamass l4 sity control means at a selected low intensity setting thereof for activating said output circuit for transfer of energy therethrough.'

4. Apparatus for production of electrical energy comprising means operable to provide a D. C. power supply, generator means for producin A. C. energy, means forming an output circuit, switch means selectively operable to connect said power supply and said generator means alternately in said output circuit, intensity control means in said output circuit and a normally open switch for holding the output circuit normally inactive, closing means operable by said intensity control means to close said switch at a selected low intensity setting of said control means whereby to activate said output circuit for transfer of energy therethrough, and holding means for maintaining said switch closed, after operation of said closing means for as long as energy is delivered in said output circuit.

5. Apparatus for production of electrical energy comprising rectifier means operable from a source of A. C. energy to provide a D. C. power supply, generator means energized from said source for producing an A. C. energy wave of desired frequency, means forming an output circuit, master switch means operable to connect said rectifier means with said source, additional switching means selectively operable to connect said power supply and said generator means. alternately in said output circuit and to connect said generator means with said source through said master switch means when said generator is connected with said output circuit, A. C. and D. C.

indicating meters, and relay switch means operable for interconnecting said meters in said output circuit as said power supply and generator means are connected therewith.

6. Apparatus for production of electrical energy comprising rectifier means operable from a source of A. C. energy to provide a D. C. power supply, generator means energized from said source for producing an A. C. energy wave of desired frequency, means forming an output circuit, master switch means operable to connect said rectifier means with said source, additional switching means selectively operable to connect said power supply and said generator means alternately in said output circuit and to connect said generator means with said source through said master switch means when said generator is connected with said output circuit, A. C. and D. C. indicating meters, and relay switch means operable for interconnecting said meters in said output circuit as said power supply and generator means are connected therewith, range selector switches for conditioning said meters for operation in desired operating ranges, and a manually operable control member for selectively operating the master switch means, said additional switching means and said range selecting switches.

'7. Apparatus for production of electrical energy comprising a pulsating wave energy generator, a motor for driving said generator having an eddy current disc, driving magnets associated with said disc and having actuating coils, means to electrically energize one of said coils at a constant energy level, means to electrically energize another of said coils at an energy level variable at will, in smooth, progressive fashion, whereby to control the speed of said motor and the output pulsating wave frequency of the connecting generator in like fashion within the frequency range of the apparatus.

8. Apparatus for production of electrical energy 'motor and of the modulating comprising a pulsating wave energy generator, a motor for driving said generator having an eddy current disc, driving magnets associated with said disc and having actuating coils, means to electrically energize one of said coils at a constant energy level, means to electricalLv energize another of said coils at an energy level variable at will, in smooth, progressive fashion, whereby to control the speed of said motor'and the output pulsating wave frequency of the connected gen erator in like fashion within the frequency range of the apparatus, drag magnet means operativelv associated with said disc and means operable at will to energize said magnet for operation of said motor in a slow speed range.

9. Apparatus for production of electrical energy comprising a generator operable to produce a carrier wave of energy of desired frequency, including modulating means operable to modulate the carrier wave, a motor for driving said modulating means, said motor having an eddy current disc, driving magnets associated with said disc and having actuating coils, means to energize one of said coils at a constant energy level, means to electrically energize another of said coils at an energy level variable at will, in smooth, progressive fashion, whereby to control the speed of said means in like fashion within the frequency range of said modulating means. v

10. Apparatus for production of electrical energy comprising a generator operable to produce a carrier wave of energy of desired frequency, including modulating means operable to modulate the carrier wave, a motor for driving said modulating means, said motor having an eddy current disc, driving magnets associated with said disc and having actuating coils, means to energize one of said coils at a constant energy level, means to electrically energize another of said coils at an energy level variable at will, in smooth, progressive fashion, whereby to control the speed of said motor and of the modulating means in like fashion within the frequency range of said modulating means, and a drag magnet means operatively associated ing a permanent magnet for causing the motor to operate at ultra slow speed.

11. Apparatus for production of electrical energy comprising a generator operable to produce a carrier wave of energy of desired frequency, including modulating means operable to modulate the carrier wave, a motor for driving said modulating means, said motor having an eddy current disc, driving magnets associated with said disc and having actuating coils, means to electrically energize said coils, said disc being formed with a perforation therethrough, on one side thereof, in position to register with said driving magnets, and means operable at will to substantially reduce the energy supplied to one of said coils whereby to stop said motor when said opening comes in registration with said driving magnets.

production of electrical energy comprising rectifier means operable from a source of A. C. energy to provide a D. C. power supply, a generator operable to produce a pulsating energy wave having a frequency component,

associated with said disc and having actuating coils, means to electrically energize said coils variably, in smooth, progressive fashion, to control the speed of said motor and the correspondwith said disc and comprising frequency of said component in like fashion, means forming an output circuit, switch means selectively operable to connect said power supply and said generator means alternately in said output circuit and to connect said power supply with said A. C. energy source, and means to connect said generator means with said A. C. energy source when the generator means is connected with said output circuit.

13. Apparatus as set forth in claim 12, including A. C. and D. C. indicating meters, and switch means operable to interconnect said meters in said output circuit selectively as said power supply and generator with.

14. Apparatus as set forth in claim 12, including an intensity control potentiometer in said output circuit and switch means for holding the output circuit normally inactive, said switching means being Operable by said intensity control means at a predetermined low intensity setting thereof for activating said output circuit for transfer of energy therethrough.

15. Apparatus for production of electrical energy comprising a pulsating energy wave generator embodying a light source, photo-electric elements, a light interrupting member movable between said light source and said photo-electric elements, an adjustable speed motor for driving said interrupting member at a selected rate within a predetermined speed range, a translation system comprising a pair of impedance matching valves controllingly connected with said photoelectric elements, a bridge network comprising input valves controllingly connected with said impedance matching valves, and output valves controllingly connected with the input valves, said photo-electric means, the impedance matching valves and the input and output valves of said bridge circuit being interconnected in push-pull relationship.

16. Apparatus as set forth in claim 15 wherein said motor comprises an eddy current disc, driving magnets associated with said discs and having actuating coils, means to electrically energize said coils to drive said disc at desired speed, and drag magnet means for reducing the operating speed of said motor.

17. Apparatus as set forth in claim 15, including means forming a supply source of uni-directional power, means forming an output circuit, switch means selectively operable to connect said supply source and said output valves alternately with said output circuit, A. C. and D. C. indicating meters, and switch means operable for interconnecting said meters in said output circuit as said supply source and output valves are interconnected therewith.

18. Apparatus as set forth in claim 15, including means forming a supply source of uni-directional power, means forming an output circuit, switch means selectively operable to connect said supply source and said output valves alternately with said output circuit, A. C. and D. C. indicating meters, switch means operable for interconnecting said meters in said output circuit as said sup ply source and output valves are interconnected therewith, intensity control means in said output circuit, and switch means for holding the output circuit normally inactive, said switch means being operable by said intensity control means at a selected low intensity setting thereof for activating said output circuit for transfer of energy therethrough.

19. Apparatus as set forth in claim 15, includmeans are connected thereing means forming a supply source of uni-directional power, means forming on output circuit, switch means selectively operable to connect said supply source and said output valves alternately with said output circuit, A. C. and D. C. indicating meters,-switch means operable for interconnecting said meters in said output circuit as said supply source and output valves are interconnected therewith, intensity control means in said output circuit, a normally open switch for holding the output circuit normally inactive, closing means operable by said intensity control means to close said switch at a selected low intensity setting of said control means, and holding means for maintaining said switch closed, after operation of said closing means, for as long as energy is delivered in said output circuit.

20. Apparatus as set forth in claim 15, wherein said adjustable speed motor comprises an eddy current disc, driving magnets associated with said disc, at least one of said magnets having an actuating coil, and means to electrically energize said coil at an energy level variable at will to control the speed of said motor and the frequency of the pulsating wave delivered from said generator.

21. Apparatus as set forth in claim 15, wherein said adjustable speed motor comprises an eddy current disc, driving magnets associated with said disc, at least one of said magnets having an actuating coil, and means to electrically energize said coil selectively at high and at substantially lower energy levels for operation of said motor selectively in high and low speed ranges.

22. Apparatus for production of electrical energy comprising a pulsating energy wave generator embodying a light source, photo-electric means, means to develop an energy wave in response to variations in light intensity on said photo-electric means, comprising a light interrupting member turnable between said light source and said photo-electric means, a motor for driving said member having an eddy current disc, driving magnets associated with said disc and having actuating coils, means to energize one of said coils at a constant energy level, means to electrically energize another of said coils at an energy level variable at will, in smooth, progressive fashion, whereby, in like fashion, to control the speed of said motor and the corresponding frequency of light interruption by said interrupting member, and a drag magnet operatively associated with said disc for causing slow speed operation of the motor.

23. Apparatus as set forth in claim 22 wherein said photo-electric means comprises a pair of spaced photo-electric elements operatively connected with a translation system for developing the pulsating energy wave in response to light beams of variable intensity applied alternately on said elements, said light interrupting member 18 comprising an opaque member formed with spaced radially extending windows through which light beams from the source may be applied alternately on said elements as said disc is rotated by said motor.

2 A rotary motor comprising a rotatable eddy current disc, a driving magnet having a potential coil, a driving magnet having a current coil, means to energize said potential and current coils for motor operation by rotation of said disc, and a drag magnet operatively associated with said disc for retarding rotation of the disc, whereby the 'motor may operate within a selected slow speed range.

25. A rotary motor comprising a rotatable eddy current disc, a driving magnet having a potential coil, a driving magnet having a current coil, means to energize said current and potential coils for motor operation by rotation of said disc in a normal speed range, a drag magnet operatively associated with said disc and means operable at will to energize said drag magnet for slow speed operation of said motor.

26. A rotary motor comprising a rotatable eddy current disc, a driving magnet having a potential coil, a driving magnet having a current coil, means to electrically energize said current and potential coils for motor operation by rotation of said disc, and means operable at will selectively to supply energy to one of said coils either at a relatively high or a relatively low intensity level, whereby to control the motor for operation in high and low speed ranges.

27. A rotary motor comprising a rotatable eddy current disc, a driving magnet having a potential coil, a driving magnet having a current coil, means to electrically energize said current and potential coils for motor operation by rotation of said disc, said disc being formed with a perforation therethrough, on one side thereof, in position to register with said driving magnets, and means operable at will to reduce the energy supplied to one of said coils whereby to stop said motor when said opening comes in registration with the poles of said driving magnets.

WILLIAM D. SHANNON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,801,385 Rose Apr. 21, 1931 1,990,023 I Eremeefl Feb. 5, 1935 2,004,751 Fisher et al June 11, 1935 2,084,904 Geise June 22, 1937 2,266,105 Vogt Dec. 16, 1941 2,269,972 Halberg Jan. 13, 1942 2,415,022 Morrison Jan. 28, 1947 

